The present invention relates generally to toys and, more particularly, to a toy that is capable of recognizing and identifying various objects placed in proximity to the toy.
Over the last several decades, toys have become increasingly sophisticated, allowing a child to interact with the toy to an ever-increasing extent. Initially the interaction between a child and the toy was quite limited. For example, during the 1960""s, several toys were introduced which included a voice playback mechanism activated by pulling a string on the back of the toy. Thus, for example, a child was able to elicit a variety of pre-recorded phrases such as xe2x80x9cHello, my name is Suziexe2x80x9d or xe2x80x9cI am hungryxe2x80x9d simply by pulling the string. Unfortunately as the pre-recorded phrases spoken by the doll were randomly ordered, the child quickly became bored with the toy.
In order to provide more positive interaction, newer toys are designed to perform a specific function in response to the child""s actions. For example, U.S. Pat. No. 4,231,184 discloses a doll assembly which raises its arms and simulates a crying sound in response to a specific frequency sound signal emitted by squeezing a specific toy baby bottle. These actions can be stopped by inserting the nipple of the bottle into the doll""s mouth, the insertion causing a switch to be opened. U.S. Pat. No. 5,290,198 discloses a more sophisticated doll assembly, one which is capable of responding both to an action on the part of the child, as well as a length of time that the action is performed. For example, by inserting the nipple of a bottle into the mouth of the doll, the doll emits a sound that simulates a baby drinking milk from a bottle. If the bottle is removed too quickly, the doll emits a sound that simulates a baby crying. In contrast, if the bottle is left in the doll""s mouth for a sufficient period of time, the doll emits a sound simulating satisfaction. Additionally, the child can elicit responses by squeezing the doll. Besides mechanical sensors, this patent also discloses the use of light and magnetic sensitive switches.
In order to provide more stimulation as well as a better learning experience to a child, some toys are designed to provide the child with a varied and relatively complex response in reaction to one or more actions performed by the child. For example, U.S. Pat. No. 5,495,557 discloses an electronic book which includes a permanent memory containing an audio data base of a plurality of words and phrases, preferably arranged within categories such as subjects, verbs, adjectives, etc. As the child activates a series of switches, for example contained on a xe2x80x98pagexe2x80x99 of the book, words and phrases are stored in a temporary memory. When the selections have been completed, for example by selecting a word or phrase within each grammar category, a complete sentence is formed. Using a voice synthesizer, the toy can then enunciate the sentence formed by the child.
Another type of interactive toy is capable of recognizing an object and providing a specific response as a result of the identity of the object. U.S. Pat. No. 5,314,336 discloses a technique for object recognition based on optical scanning. Specifically, the disclosed system houses an optical scanner in the toy which is capable of recognizing markings, such as bar codes, which are located on the object to be recognized. Unfortunately, toys utilizing optical scanners are typically expensive and relatively sensitive to breakage due to the use of optical components. Additionally, a child may find such a toy difficult and frustrating to use due to the conditions placed on scanning, i.e., a specific scanning path, direction, and speed. Lastly, the use of an optical scanner places design constraints on the object, specifically the object must include a suitable region to which the optical code can be affixed and this region must be kept relatively clean in order to insure proper scanning.
Other object recognition systems require physical contact between the master toy and the object, physical contact either allowing selective closure of encoding switches or completion of an electrical object identification circuit. Since this approach requires that the toy and the object be in physical contact, proximity identification is not allowed. This type of system also places various design constraints on both the toy and the object due to the required mating surfaces. Additionally, the master toy/object interconnections (e.g., switch pins, conductive connectors, etc.) are prone to failure due to damage resulting from contamination, scratching, or breakage.
Accordingly, what is needed is an object recognition system that is relatively inexpensive, places minimal design constraints on both the master toy and the object to be recognized, and does not require the toy and the object to be in physical contact. The present invention provides such a system.
The present invention provides a method and apparatus for allowing one toy, i.e., a master toy, to identify a plurality of other toys, i.e., objects, that are brought into proximity to the master toy. The sensing circuitry of the present invention does not require that the master toy and the object be placed in physical contact with one another, thus eliminating the need for electrical contacts, locating pins and surfaces, and/or switching pins. As a result, less design constraints are placed on the toy designer regarding size, shape, and texture. Additionally, toys utilizing this invention are generally less prone to failure than toys that use external electrical contacts that can corrode, or toys that use pins and the like which can be damaged by a small child, thus making the toy inoperative for its intended function.
The present invention relies on inductively coupling a remote circuit within the object to be identified with a sensing circuit within the master toy. The sensing circuit within the toy is a variable frequency RF oscillator, preferably controlled by an internal microprocessor. The RF oscillator uses an air wound coil to radiate a magnetic flux which couples to the air surrounding the coil. The object to be identified includes one or more tuned tank circuits, each of which may be comprised of an inductor and a capacitor or an inductor and either a crystal or a resonator, the resonant frequency or frequencies of the one or more tank circuits serving as a signature for the object. The approach of using an inductor coupled to either a crystal or a resonator is preferred as it offers both improved object discrimination and sensing range.
In at least one embodiment of the invention, the frequency of the RF oscillator is varied over a range of frequencies, preferably utilizing a series of preset output frequencies. While the frequency of the oscillator is varied, the current drawn by the oscillator is monitored. When an object containing a tank circuit becomes inductively coupled to the oscillator, the output coil of the oscillator circuit becomes loaded which affects the current drawn by the oscillator. If the oscillator frequency substantially corresponds to the resonant frequency of a tank circuit, the current drawn by the oscillator will be at a minimum.
In at least one other embodiment of the invention, the object identifying function of the master toy is broken up into an oscillation generating step and an oscillation sensing step. During the sensing step, the master toy monitors for ringing emitted by a tank circuit of an object, the ringing due to the oscillation of the tank circuit after the oscillation stimulus has been removed. Since two separate steps are used during sensing, the receiver circuit can include signal amplification circuitry which results in a greater object sensing range.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings.